Last week a man left a case with a rare Picasso in it in a subway station. “The man who found it is a mystery. But he, in turn, left it leaning against a wall on the Upper West Side, under a poster advertising bagels. The next man to find it, a sidewalk book vendor, took it home to Queens. He liked the portfolio. No idea there was a Picasso in there, and he would not have picked it out if he had looked. Just another drawing of two guys on a bench. But soon, it was all over the papers, and his wife figured it out first. He called the man who lost the portfolio and inquired about the reward. Next thing he knew, the police were waiting for him at his corner today when he showed up for work.”